--- a/make-rules/prep-unpack.mk	Tue Apr 11 20:19:32 2017 -0700
+++ b/make-rules/prep-unpack.mk	Wed Apr 12 14:48:14 2017 -0700
@@ -20,7 +20,7 @@
 #
 
 #
-# Copyright (c) 2010, 2016, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2010, 2017, Oracle and/or its affiliates. All rights reserved.
 #
 
 UNPACK =		$(WS_TOOLS)/userland-unpack
@@ -54,6 +54,8 @@
 SOURCE_DIR$(1) = $$(COMPONENT_SRC$(1):%=$$(COMPONENT_DIR)/%)
 
 UNPACK_STAMP$(1) =	$$(SOURCE_DIR$(1):%=%/.unpacked)
+else
+CLEAN_PATHS += $$(SOURCE_DIR$(1))/.prep
 endif
 endef